A Method for Evaluating the Cumulative Impact of Ground-Based Logging Systems on Soils

A method for determining the Effective Ground Pressure (EGP) of tracked or wheeled logging machines that can be directly and unambiguously related to their impact on soils is described. When several machines operate together in a logging system, the methodology allows their individual EGP's to be combined to derive a System Effective Ground Pressure (SEGP), which measures the impact of the system as a whole. The methodology has been applied to determine the relative impact of logging systems and influence the choice of machine running gear. Given also the temporal variability in the bearing capacity of soils, it has also been applied to forecasting the minimum level of disruption to operations on flat ground arising from limitations placed on soil disturbance. These applications have led to increased efficiency of operations through a reduction in wood stockpiling during wet weather. The method is sufficiently simplistic at the core, that contractors with the aid of appropriate charts have evaluated the relative impact of machines and systems on soils themselves

The role of 1,25-dihydroxyvitamin D in the inhibition of bone formation induced by skeletal unloading

Skeletal unloading results in osteopenia. To examine the involvement of vitamin D in this process, the rear limbs of growing rats were unloaded and alterations in bone calcium and bone histology were related to changes in serum calcium (Ca), inorganic phosphorus (P sub i), 25-hydroxyvitamin D (25-OH-D), 24,25-dihydroxyvitamin D (24,25(OH)2D and 1,25-dihydroxyvitamin D (1,25(OH)2D. Acute skeletal unloading induced a transitory inhibition of Ca accumulation in unloaded bones. This was accompanied by a transitory rise in serum Ca, a 21% decrease in longitudinal bone growth (P 0.01), a 32% decrease in bone surface lined with osteoblasts (P .05), no change in bone surface lined with osteoclasts and a decrease in circulating (1,25(OH)2D. No significant changes in the serum concentrations of P sub i, 25-OH-D or 24,25(OH)2D were observed. After 2 weeks of unloading, bone Ca stabilized at approximately 70% of control and serum Ca and 1,25(OH)2D returned to control values. Maintenance of a constant serum 1,25(OH)2D concentration by chronic infusion of 1,25(OH)2D (Alza osmotic minipump) throughout the study period did not prevent the bone changes induced by acute unloading. These results suggest that acute skeletal unloading in the growing rat produces a transitory inhibition of bone formation which in turn produces a transitory hypercalcemia

Water pollution affects fish community structure and alters evolutionary trajectories of invasive guppies (Poecilia reticulata).

Anthropogenic habitat alterations have the potential to affect both, ecological dynamics of communities and populations, as well as evolutionary processes within populations. Invasive species may benefit from anthropogenic disturbance, such as water pollution, to which they sometimes seem more resistant than native ones. They also allow investigating evolutionary divergence among populations occurring along pollution gradients. We assessed fish communities at 55 sampling sites in the degraded and heavily overstocked Mutara Rangelands of north-eastern Rwanda (upper Nile drainage), which receive pollution from domestic wastewater and cattle dung. Diverse fish communities became apparent that included invasive guppies (Poecilia reticulata, Poeciliidae), and canonical correspondence analyses found significant differentiation of community structures along several environmental parameters (condensed into principal components), including pollution-effects. As predicted, generalized linear models found guppies to have a higher likelihood of occurrence at polluted sites. Local abundances of guppies, however, decreased at polluted sites. Since guppies are color-polymorphic, and color patterns have a heritable basis, they allow inferences regarding both pollution-induced suppression of male ornamentation (e.g., through xenestrogens) and evolutionary population divergence. We thus quantified different ornament types (numbers and percent body surface cover). ANCOVAs uncovered several weak (based on effect strengths), but statistically significant pollution-effects and interactions with other environmental parameters. The direction of several interaction effects was similar for blue/black and red/orange ornaments, while white/iridescent ornaments responded dissimilarly. As responses differed between ornament types, they likely reflect evolutionary divergence due to site-specific alterations of selective regimes rather than developmental inhibition of male secondary sexual characters. We propose that pollution affects local fitness landscapes resulting, e.g., from predation and mate competition (as a function of local abundances), altogether driving evolutionary divergence of sexually selected traits. This study highlights how human activities not only impact ecological dynamics, but-mediated by altered Eco-Evo dynamics-might change the evolutionary trajectories of populations

Stress distribution correlated with damage in duplex stainless steel studied by synchrotron diffraction during plastic necking

The goal of this work was the determination of lattice strains distribution in two phases of duplex steel during plastic necking. Subsequently, the stress heterogeneity in the neck was studied in order to determine the reason for the damage initiation and to verify the hypothesis that the damage begins in the ferritic phase. To do this, X-ray synchrotron radiation was used to scan the ‘in situ’ variation of the interplanar spacings along the necking zone for samples subjected to tensile loading. A self-consistent model and FEM simulation were applied for the experimental data interpretation. It was found that for advanced necking the phase lattice strains, especially those measured at some distance from the neck centre, show a large inversion of the loads localised in both phases compared to the undamaged state (the lattice strains in the ferrite become smaller than in the austenite). This effect indicates stress relaxation in the ferrite which is connected with the damage phenomenon. Correlation of the experimental results with the modelling shows that the value of von Mises stress is responsible for the initiation of the ferritic phase softening

Bone Degeneration and Recovery after Early and Late Bisphosphonate Treatment of Ovariectomized Wistar Rats Assessed by In Vivo Micro-Computed Tomography

Bisphosphonates are antiresorptive drugs commonly used to treat osteoporosis. It is not clear, however, what the influence of the time point of treatment is. Recently developed in vivo micro-computed tomographic (CT) scanners offer the possibility to study such effects on bone microstructure in rats. The aim of this study was to determine the influence of early and late zoledronic acid treatment on bone in ovariectomized rats, using in vivo micro-CT. Twenty-nine female Wistar rats were divided into the following groups: ovariectomy (OVX, n = 5), OVX and zoledronic acid (ZOL) at week 0 (n = 8), OVX and ZOL at week 8 (n = 7), and sham (n = 9). CT scans were made of the proximal tibia at weeks 0, 2, 4, 8, 12, and 16; and bone structural parameters were determined in the metaphysis. Two fluorescent labels were administered to calculate dynamic histomorphometric parameters. At week 16, all groups were significantly different from each other in bone volume fraction (BV/TV), connectivity density, and trabecular number (Tb.N), except for the early ZOL and control groups which were not significantly different for any structural parameter. After ZOL treatment at week 8, BV/TV, structure model index, Tb.N, and trabecular thickness significantly improved in the late ZOL group. The OVX and ZOL groups showed, respectively, higher and lower bone formation rates than the control group. Early ZOL treatment inhibited all bone microstructural changes seen after OVX. Late ZOL treatment significantly improved bone microstructure, although the structure did not recover to original levels. Early ZOL treatment resulted in a significantly better microstructure than late treatment. However, late treatment was still significantly better than no treatment

Long-term survival in patients with non-small cell lung cancer and synchronous brain metastasis treated with whole-brain radiotherapy and thoracic chemoradiation

<p>Abstract</p> <p>Background</p> <p>Brain metastases occur in 30-50% of Non-small cell lung cancer (NSCLC) patients and confer a worse prognosis and quality of life. These patients are usually treated with Whole-brain radiotherapy (WBRT) followed by systemic therapy. Few studies have evaluated the role of chemoradiotherapy to the primary tumor after WBRT as definitive treatment in the management of these patients.</p> <p>Methods</p> <p>We reviewed the outcome of 30 patients with primary NSCLC and brain metastasis at diagnosis without evidence of other metastatic sites. Patients were treated with WBRT and after induction chemotherapy with paclitaxel and cisplatin for two cycles. In the absence of progression, concurrent chemoradiotherapy for the primary tumor with weekly paclitaxel and carboplatin was indicated, with a total effective dose of 60 Gy. If disease progression was ruled out, four chemotherapy cycles followed.</p> <p>Results</p> <p>Median Progression-free survival (PFS) and Overall survival (OS) were 8.43 ± 1.5 and 31.8 ± 15.8 months, respectively. PFS was 39.5% at 1 year and 24.7% at 2 years. The 1- and 2-year OS rates were 71.1 and 60.2%, respectively. Three-year OS was significantly superior for patients with N0-N1 stage disease vs. N2-N3 (60 vs. 24%, respectively; Response rate [RR], 0.03; <it>p</it>= 0.038).</p> <p>Conclusions</p> <p>Patients with NSCLC and brain metastasis might benefit from treatment with WBRT and concurrent thoracic chemoradiotherapy. The subgroup of N0-N1 patients appears to achieve the greatest benefit. The result of this study warrants a prospective trial to confirm the benefit of this treatment.</p

Prognostic factors for outcomes after whole-brain irradiation of brain metastases from relatively radioresistant tumors: a retrospective analysis

<p>Abstract</p> <p>Background</p> <p>This study investigated potential prognostic factors in patients treated with whole-brain irradiation (WBI) alone for brain metastases from relatively radioresistant tumors such as malignant melanoma, renal cell carcinoma, and colorectal cancer. Additionally, a potential benefit from escalating the radiation dose was investigated.</p> <p>Methods</p> <p>Data from 220 patients were retrospectively analyzed for overall survival and local control. Nine potential prognostic factors were evaluated: tumor type, WBI schedule, age, gender, Karnofsky performance score, number of brain metastases, extracerebral metastases, interval from diagnosis of cancer to WBI, and recursive partitioning analysis (RPA) class.</p> <p>Results</p> <p>Survival rates at 6 and 12 months were 32% and 19%, respectively. In the multivariate analysis, WBI doses >30 Gy (p = 0.038), KPS ≥70 (p < 0.001), only 1-3 brain metastases (p = 0.007), no extracerebral metastases (p < 0.001), and RPA class 1 (p < 0.001) were associated with improved survival. Local control rates at 6 and 12 months were 37% and 15%, respectively. In the multivariate analyses, KPS ≥70 (p < 0.001), only 1-3 brain metastases (p < 0.001), and RPA class 1 (p < 0.001) were associated with improved local control. In RPA class 3 patients, survival rates at 6 months were 10% (35 of 39 patients) after 10 × 3 Gy and 9% (2 of 23 patients) after greater doses, respectively (p = 0.98).</p> <p>Conclusions</p> <p>Improved outcomes were associated with WBI doses >30 Gy, better performance status, fewer brain metastases, lack of extracerebral metastases, and lower RPA class. Patients receiving WBI alone appear to benefit from WBI doses >30 Gy. However, such a benefit is limited to RPA class 1 or 2 patients.</p